Tangier disease diagnosis

The findings of virtual HDL deficiency and low levels of apoA-I are not sufficient for the diagnosis of Tangier disease, which ultimately requires ABCA1 gene sequence... 

Parallel analysis of control skin fibroblasts from normolipidemic donors and, ideally from patients with established diagnosis of Tangier disease, is needed. In addition,... 

Subsequently, serum lipid and lipoprotein profiles were obtained 70 mg/dL total cholesterol (normal is 130-200 mg/dL), 1 mg/dL HDL cholesterol (optimal is > 60 mg/dL), 180 mg/dL triglycerides (normal is 100-150 mg/dL), and less than 5 mg/dL apolipoprotein A-I (apoA-I normal is 140 mg/dL). Cholesterol efflux from patient skin fibroblasts to apoA-I, the main protein component of HDL, was reduced to 30% of normal. These results indicated Tangier disease, the definitive diagnosis of which was made when the sequencing of the ATP-binding cassette transporter A1 (ABCA /) gene revealed a nonsense mutation within exon 12. 

Profiling of plasma lipoproteins and serum lipids can often aid in the diagnosis of Tangier disease. There are four classes of lipoproteins (1) chylomicrons, which transport dietary cholesterol and triglycerides from the intestines to the tissues (2) very low-density lipoproteins (VLDL) and (3) low-density lipoproteins (LDL), both of which transport de novo synthesized cholesterol and triglyceride from the liver to the tissues and (4) high-density lipoproteins (HDL), which mediate reverse cholesterol transport, a process in which excess cholesterol from peripheral tissues is transported to the liver. 

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